In general, in electronic apparatuses such as personal computers, PDAs, mobile phones, game machines and TVs, various sensors are used for supporting operations of such electronic apparatuses by the user. A proximity sensor is known as one of such sensors. The proximity sensor is a sensor for detecting an object (e.g. a person) that is present within a range of detection. The proximity sensor can be used in order to detect whether an object which is in proximity to the electronic apparatus is present or not.
Jpn. Pat. Appln. KOKAI Publication No. 2009-169627 discloses a notebook personal computer including a display which is equipped with an infrared sensor. In this computer, the infrared sensor is used in order to determine whether a person, who operates the computer, is present or not.
However, in this computer, no consideration is given to the adjustment of the detection distance (also referred to as “detection range”) of the sensor (infrared sensor).
In general, the distance between the user and the computer at a time when the user operates the computer varies from user to user. Even in the case of the same user, the distance between the user and the computer varies depending on the environment of use of the computer (e.g. an environment in which a notebook computer is used on the desk, an environment in which a notebook computer is used on the lap, etc.). Thus, a proper detection distance of the sensor may possibly vary depending on users or the environment of use of the computer.
If the detection distance of the sensor is too short, it is possible that such a situation occurs that the position of the user falls out of the detection range of the sensor, depending on the variation in attitude of the user, even while the user stays in front of the computer.
Conversely, if the distance of detection of the sensor is too long, it is possible that the sensor detects a far object (e.g. a chair, a person passing behind the user's desk, etc.) as a proximity object, despite the user being absent in front of the computer. In this case, although the user is not present in front of the computer, the same operation as when the computer and the user are in a close proximity state may be executed on the computer.